Shotshell wad structure



Feb. 27, 1962 A. s. YEoMANs, JR 3,022,731

sHoTsHELL wAD STRUCTURE Filed May l2, 1959 FMG-1 FMG-2 une@Seesen-encina 3,022,731 SHGTSHELL WAD STRUCTURE Arthur S. Yeomans, Jr.,North Haven, Conn., assignor to Olin Mathieson Chemical Corporation, acorporation of Virginia `Filed May 12, 1959, Ser. No. 812,768 1 Claim.(Cl. 102-42) The present invention relates to cartridges and inparticular to wad assemblies utilized in cartridges.

In the subsequent description of the several disclosed embodiments ofthe invention, as well as in the claim, the language cartridge isintended to include so-called shotshells.

In addition, it is intended that the invention will nd equal applicationin cartridges powered by any fast burning propellant be it liquid orpowder.

Furthermore, the invention is readily adaptable to cartridges carrying asingle projectile or bullet as well as to cartridges carrying aplurality of projectiles commonly termed shot A feature of the inventionis the provision of a novel cartridge.

A further feature of the invention is the provision of a novel cartridgewad assembly.

A still further feature of the invention is the provision of anexceedingly tight gas sealV means between the propellant cavity and theprojectile cavity of a cartridge.

A further feature of the invention is the provision of a cartridge wadassembly including several wad elements and a cartridge case wherein onewad element is eective to contact and to drive another wad element intotight contact with the interior of the cartridge case thereby effectinga positive gas seal.

A cartridge wad assembly embracing certain principles of the inventionmay comprise a tubular cartridge case or body having a propellant cavityand a projectile cavity separated by a two element wad, one wad elementbeing formed with a concave contour and the other wad element beingformed with a convex contour, said elements being operative to engageone another in the region of said contours so that one element iseective to swell the other radially to develop a peripheral seal in theinterior of the cartridge case.

Other features and advantages will become more apparent from thesucceeding specification when read in conjunction with the appendeddrawings, in which:

FIG. l is an elevational view,`partially in section, showing oneembodiment of the invention.

FIG. 2 is a similar view of another arrangement of the invention, and

FIG. 3 is still another embodiment of the invention.

Referring now to the drawings, the reference numeral represents acartridge having a body or case 11 embracing a projectile cavity 12 anda propellant cavity 13.

Disposed between and physically separating the projectile cavity and thepropellant cavity is a pair of wads comprising a wad element 14 having agenerally concave contour as at 16 and a wad element 17 having agenerally convex contour as at 18.

The respective concave and Vconvex contours are disposed in nestedrelationship and normally make a line contact as at 19.

i, 3,022,731 Patented Feb. 27, 1062 While the particular convex andconcave contours of the disclosed embodiments of the wad elements denecones making circular line contact, it is not intended that the contoursbe so limited. As will be more apparent hereinafter, any generallyconcave and convex surfaces will suffice so long as there is a wedgingaction between the wads in which the lower wad (wad 17) tends to flare,swell or mushroom the upper wad element radially into tight peripheralcontact with the interior of the cartridge case.

In the FIG. l embodiment of the invention a so-called cup wad 21(cup-shaped) is disposed between the wad element 17 and the propellantcavity as an individual element.

In the embodiment of FIG. 2, the cup wad is formed integral with the wadelement nearer to the propellant cavity wherein the wad 17 is formedwith a skirt 23.

The FIG. 3 embodiment illustrates another individual wad elementdefining an H wad 24 disposed between the.

wad element 17 and the propellant cavity 13. The wad 24 obviouslyincludes a cup-like structure.

Upon activation of propellant within the cavity 13 utilizing a primer 26in well-known fashion, the propellant burns rapidly to generate hotgases developing pressures of the order of 8,000 to 10,000 p.s.i.

'I'he gas pressure rst operates upon the cup-like structure of the wadassembly driving the skirts or llanges 23, 27 and 28 into tight gassealing contact with the periphery of the interior of the cartridgecase.

Instantaneously the gas pressure begins to drive the cup-like portion ofthe wad assembly away from the propellant cavity with the result thatthe next adjacent wad element 17 is driven into wedging relationshipwith the upper wad 14.

The wedging action, which occurs because the slope of the contour of thelower wad is flatter than the slope of the upper wad, is elective toliare, swell or mushroom the upper wad in a radial direction eiective tocreate an even tighter gas seal between the interior of the cartridgecase.

The occurrence of the wedging action also affords cushioned but positivethrust in driving the projectile from the projectile cavity. Thecushioned effect is a function of the space between the contoured wadsand is increased, of course, by certain cup wad structures such as the Hwad of FIG. 3.

In operation, the cup-like structure of the wad assembly may be thoughtof as creating a primary seal while the combined concave and convexcontoured elements thereof create a secondary seal and virtually insurea gas tight barrier or gas tight piston between the propellant cavityand the projectile cavity.

What is claimed is:

In a shotshell having a propellant cavity and a shot column separated bya cup wad defining a primary seal, the improvement which comprises apair of cooperating wads disposed between the shot column and theprimary `seal effective to create a secondary seal, said cooperatingtangent to said concave face at at least two points being less than theradius of curvature of a circle described References Cited in the fileof this patentv UNITED STATES PATENTS Holmes Jan. 8, 1952 FOREIGNPATENTS France June 20, 1938 Germany July 16, 1909 Germany Sept. 15,1909 France May 28, 1956 France Mar. 4, 1957

